Viral Test for COVID-19

Why It Is Done

This test is used to diagnose a current infection with SARS-CoV-2, the virus that causes COVID-19. Knowing that you have the virus means that you can take steps to protect others from getting infected. This can help limit the spread of the virus.

Your doctor may have you take the test to find out if you have the virus. If you have the virus, they may have you take medicine to help prevent serious illness. Treatment works best when it's started early.

Get tested right away if you have COVID-19 symptoms. If your test is positive, let your doctor know.

How It Is Done

The test is most often done on a sample from your nose or throat. It's sometimes done on a sample of saliva. One way a sample is collected is by putting a long swab into the back of your nose. Samples can be tested in different ways to look for an infection.

Results

The result is either positive or negative.

A positive result means that the antigen or the genetic material of the virus was found in your sample. You have COVID-19 now. If your test is positive, talk to your doctor about what you need to do.

A negative result means that the antigen or the genetic material was not found. This may mean that you don't have COVID-19. If your test is negative, follow your doctor's advice for when you can go back to activities.

But it's possible to get a "false-negative" result. This means that the test shows that you don't have COVID-19 when in fact you do. This may happen because you were tested too soon after you were infected, before the virus started to spread in your nose and throat. Or it could happen because the swab missed the infection.

If you get a negative result for an antigen test, your doctor may recommend that you get another test, such as polymerase chain reaction (PCR), to make sure you don't have the virus. You may need to take the same test again to make sure you don't have the virus.

Waiting for your test results

Some test results come back in a few minutes. Others may take a few days. What to do while you wait for your results depends on why you got the test.

• If you have COVID-19 symptoms:

  Wear a mask around other people, avoid travel, and stay away from people who are at high risk of serious COVID illness for at least 10 days. Stay in the place where you live. Separate yourself from others.

• If you were exposed to someone with COVID-19 AND you don't have symptoms AND you are up to date on your COVID-19 vaccines or you tested positive for the COVID virus in the last 3 months and have recovered:

  Wear a mask around other people, avoid travel, and stay away from people who are at high risk of serious COVID illness for at least 10 days.

• If you were exposed to someone with COVID-19 AND are NOT up to date on your COVID-19 vaccines AND have NOT tested positive for and recovered from the COVID virus in the last 3 months:

  Wear a mask around other people, avoid travel, and stay away from people who are at high risk of serious COVID illness for at least 10 days. Stay in the place where you live. Separate yourself from others.

• If you are currently self-isolating because you have COVID-19 OR if you were exposed and are testing to see if you can leave quarantine before 10 days:

  Wear a mask around other people, avoid travel, and stay away from people who are at high risk of serious COVID illness for at least 10 days. Stay in the place where you live. Separate yourself from others.

• If you are testing for a reason like work, school, or travel, or before visiting indoors with people you don't live with:

  You don't need to do anything special. Follow the cdc.gov and local health guidelines about things like wearing a mask and physical distancing.